WE bought our house new in "88, we have a Gerber Mark II tank, it recently got broken. All the replacement tank bolt patterns do not line up with the bowl. The old tank is 6 5/8, the new ones are 5 7/8, my husband bent the screws to make them go into the holes. I belive this should not be done, am I right? We can't find a repleacement tank anywhere. Help!